Where Does Up-Scaling Begin?
Lets Put Geology Back into Geostatistics Christian J. Heine Saudi Aramco, Dhahran, Saudi Arabia Historically, a geocellular model was considered good, if the porosity distribution of the interpolated grid matched the porosity distribution of the input well data. While in some cases this might be an acceptable result; in a reservoir where contacts between bed units are sharp, attributes such as porosity tend to get smoothed across the bed boundary and become part of the statistics. Let the up scaling begin Logging tools such as gamma-ray, sonic, density and neutron measure varying volumes of rock and have varying depths of investigation in the wellbore. Gamma-ray, for example measures a three foot window for each recorded sample and samples are recorded every foot. This translates into 3-samples of transition measurement on each side of a sharp bed contact. If the reservoir unit being measured is not at least four feet thick, a logging tool may never achieve a true reading of the reserv
